This project is designed to prepare a GMP quality investigational HIV vaccine and complete the preclinical and laboratory studies needed to initiate clinical trials of an investigational multicomponent HIV recombinant modified vaccine Ankara (rMVA) vaccine (rMVA HIV). The vaccine consists of a highly attenuated vaccinia virus that cannot replicate in human cells which has been genetically recombined with genes expressing Gag, Pol and Envelope proteins from HIV-1. The first clinical trial will be a phase I, randomized, controlled, double-blinded, dose-escalation study to examine tolerability, dose, and immune response. Healthy uninfected volunteers will be enrolled. The hypothesis is that MVA will be safe in humans when administered by intramuscular (IM) injection and will result in an immune response. Subjects will be randomized to injections of rMVA HIV or placebo. Safety and immunogenicity lab tests will be done throughout the studies.